• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2000.04a
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• pp.112-118
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• 2000

Densification behavior of mixed copper and tool steel powder under cold compaction was investigated. By mixing the yield functions proposed by Fleck et al. and by Gurson for pure powder in terms of volume fractions and contact numbers of Cu powder new mixed yield functions were employed for densification of powder composites under cold compaction. The constitutive equations were implemented into a finite element program (ABAQUS) to compare with experimental data for densificatiojn of mixed powder under cold isostatic pressing and cold die compaction. finite element calculations by using the yield functions mixed by contact numbers of Cu powder agreed better with experimental data than those by volume fractions of Cu powder.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.393-398
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• 2000

Densification behavior of mixed copper and tool steel powder under cold compaction was investigated. By mixing the yield functions originally proposed by Fleck-Gurson for pure powder, a new mixed yield functions In terms of volume fractions and contact numbers of Cu powder were employed in the constitutive models. The constitutive equations were implemented into a finite element program (ABAQUS) to compare with experimental data. and with calculated results from the model of Kim et at. for densification of mixed powder under cold isostatic pressing and cold die compaction. Finite element calculations by using the yield functions mixed by contact numbers of Cu powder agreed better with experimental data than those by volume fractions of Cu powder.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.24 no.10 s.181
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• pp.2628-2636
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• 2000

Densification behavior of mixed copper and tool steel powder under cold compaction- was investigated. By mixing the yield functions proposed by Fleck et al. and by Gurson for pure powder in terms o f volume fractions and contact numbers of Cu powder, new mixed yield functions were employed for densification of powder composites under cold compaction. The constitutive equations were implemented into a finite element program (ABAQUS) to compare with experimental data and with calculated results from the model of Kim et al. for densification of mixed powder under cold isostatic pressing and cold die compaction. Finite element calculations by using the yield functions mixed by contact numbers of Cu powder agreed better with experimental data than those by volume fractions of Cu powder.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.647-650
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• 2001

The purpose of this study was the influence of cold weather ready mixed concrete quality according to needs of customer were investigated by measurements of slump, air content, temperature and compressive strength. As a results, cold weather ready mixed concrete using high standard admixtures, high early strength admixtures and cold weather concrete plant were similarly to slump, air content, temperature and compressive strength.

• Journal of the Korean Society of Food Culture
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• v.26 no.4
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• pp.307-313
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• 2011

The main purpose of this study was to perform a literature review regarding bibimnaengmyeon (cold buckwheat noodles mixed with sauce)-related recipes. To conduct this research, we analyzed recipe data published in Korea from the 1800's to the 1980's. The research was conducted by content analysis and literature review. The documents used in the research were 30 books (dictionaries and recipe books). A total of 37 bibimnaengmyeon-related recipes were identified. The results of the analysis of documented data published within the last 200 years showed two different types of main ingredients for bibimnaengmyeon-related recipes; noodles based on buckwheat flour, and noodles based on wheat flour. Additionally, the bibimnaengmyeon-related recipes were divided according to the sauce; 1) noodles mixed with red pepper sauce and 2) noodles mixed with soy sauce.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.26 no.7
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• pp.1324-1331
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• 2002

Densification behavior of composite powders was investigated during cold compaction. Experimental data were obtained for aluminum alloy powder mixed with zirconia powder inclusion under triaxial compression. The Cap model with constraint factors was implemented into a finite element program (ABAQUS) to simulate compaction responses of composite powders during cold compaction. Finite element results were compared with experimental data for densification behavior of composite powders under cold isostatic pressing and die compaction. The agreements between experimental data and finite element calculations from the Cap model with constraint factors were good.

• Journal of the Korean Society of Hazard Mitigation
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• v.3 no.1 s.8
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• pp.133-140
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• 2003

The research was performed to evaluate the cracking resistance characteristics of cold-mixed reclaimed asphalt pavement (RAP) using indirect tensile strength test and fatigue tests. Indirect tensile tests were conducted to estimate the indirect tensile strength at variable temperatures($10^{\circ}C\;and\;20^{\circ}C$). Fatigue tests were also carried out using 500kgf, 400kgf, and 300kgf of dynamic loads, and the fatigue life (Nf) for each mixture was measured. Indirect tensile strength of cold-mixed reclaimed asphalt pavement was about 90% of conventional 13mm dense-graded asphalt mixture. Fatigue life of cold-mixed reclaimed asphalt mixture was 70%, 55%, 30% (for 500kgf, 400kgf, 300kgf of load level, respectively) of the conventional one.

• Journal of Korean Institute of Industrial Engineers
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• v.39 no.2
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• pp.90-98
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• 2013

The k-out-of-n system with mixed redundancy is defined as k-out-of-n system which both includes warm-standby and cold-standby components. In case that operating components in the system fail and the system needs quick transition of standby components to operation state, the k-out-of-n system with mixed redundancy is useful for decreasing system failure rate and operational cost. Reliability-Redundancy Optimization Problem (RROP) involves selection of components with multiple choices and redundancy levels for maximizing system reliability with constraints such as cost, weight, etc. A solution methodology by using harmony search algorithm for RROP of the k-out-of-n system with mixed redundancy to maximize system reliability was suggested in this study.

• Transactions of the Korean hydrogen and new energy society
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• v.31 no.1
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• pp.33-40
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• 2020

As hydrogen utilization becomes more active recently, a large amount of hydrogen should be supplied safely. Among the three supply methods, liquefied hydrogen, which is an optimal method of storage and transportation convenience and high safety, has a low temperature of -253℃, which is complicated by the liquefaction process and consumes a lot of electricity, resulting in high operating costs. In order to reduce the electrical energy required for liquefaction and to raise the efficiency, hydrogen is cooled by using a mixed refrigerant in a precooling step. The electricity required for the precooling process of the mixed refrigerant can be reduced by using the cold energy of LNG. Actually, LNG cold energy is used in refrigeration warehouse and air liquefaction separation process, and a lot of power reduction is achieved. The purpose of this study is to replace the electric power by using LNG cold energy instead of the electric air-cooler to lower the temperature of the hydrogen and refrigerant that are increased due to the compression in the hydrogen liquefaction process. The required energy was obtained by simulating mixed refrigerant (MR) hydrogen liquefaction system with LNG cold heat and electric system. In addition, the power replacement rate of the electric process were obtained with the pressure, the temperature of LNG, the rate of latent heat utilization, and the hydrogen liquefaction capacity, Therefore, optimization of the hydrogen liquefaction system using LNG cold energy was carried out.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.242-247
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• 2009

The present study has been conducted to reduce the cold air drying rate. According to the cold air drying method, the quality-excellent product could be made and there would be little change of color, taste and smell. As compared with the hot air drying, the cold air drying equipment has the superior dehumidification in a constant drying zone. However, in a falling drying zone that equipment is not energy-efficient because the drying period could be longer by the dehumidificated.